well the newspaper that kim out becky flowers of the university of colorado, took a series of readings on the eastern and western portions of the river which measured a helluous isotope which stops es kate-- escaping at -- 0 degrees. you can tell how the rocks have been rising out of center of the earth and sort of pinpoint where the depth had been. and they came to the conclusion that there was a grand canyon there some 70 million years ago before the river. well, how would that be? well, they say there were actually two rivers, one that flowed one direction 70 million years ago. another that flowed the other direction 50 million years ago and that made a canyon which now the colorado river uses, make sense? >> warner: meaning what the other river disappeared. >> pretty much. >> warner: now there are real debunkers in this. >> yes, indeed carl carl's trom who speaks on we half of a large community of scientists says no that is not true. they do believe there were canyons there of that vintage but was it a grand canyon. so in many many senses this might be kind of a semantic debate. bu